The conventional dimensional regularization (CDR)By the acronym “CDR”
we refer in this article to the usual CDR [1]} where,
in addition, \(\gamma _5\)  is treated by Larin's prescription [2]}, [3]}.
scheme [1]} is a very popular RS, where all vector bosons are treated as D-dimensional objects.
It is conceptually the simplest one and does guarantee a consistent treatment.
It is typically employed in calculating (unpolarized) amplitude interferences
where the sum over the polarizations of an external particle is conveniently made
by using the respective unpolarized Landau density matrix.
For computing helicity amplitudes at the loop level, the two commonly used RS
are the 't Hooft-Veltman (HV) scheme [5]}
and the Four-Dimensional-Helicity (FDH) scheme [6]}, [7]}.
In the FDH, the usage of spinor-helicity representations [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}
and unitarity-cut based methods [17]}, [18]}, [19]}, [20]}, [21]} lead to compact expressions
for helicity amplitudes, which are computationally very advantageous,
while the proper renormalization procedure for non-supersymmetric theories beyond one loop order
requires some expertise [22]}, [23]}, [24]}, [25]}.
Another widely used dimensional regularization variant, the Dimensional-Reduction (DRED) scheme [26]},
was initially devised for application to supersymmetric theories and was later shown to be applicable also
to non-supersymmetric theories [27]}, [28]}.
The DRED and FDH have much in common, while there are also subtle differences
between the two [7]}, [23]}, [31]}, [32]}.
